This invention relates to an air flow rate measuring apparatus used especially for measuring the flow rate of air being sucked into an internal combustion engine.
In a conventional air flow rate measuring apparatus of this kind disclosed in, for example, U.S. Pat. No. 3,824,966, the temperature of a thin air flow sensor is maintained at a predetermined level by means of a temperature sensor and a temperature controlling electric circuit.
Such an air flow sensor is adversely affected by thermal disturbance occurring due to heat transmitted thereto through a supporting member consisting of, for example, metal. The thermal disturbance results in an error in the measurement of the flow rate of air.
Another type of conventional air flow rate measuring apparatus is disclosed in, for example, U.S. Pat. No. 4,121,549. In this apparatus, an air flow sensor is provided in a by-pass branched from a main duct but no consideration is given to the influence of heat upon the air flow sensor.